Lets talk good news for a change.

Auto sales may be down drastically, possibly coming in at around 10 million vehicles nationwide this year. That's a decrease of 70 percent or so from the highs of more than 17 million just a few years ago.

And certainly there have been casualties with both Chrysler and General Motors metamorphosing in front of our eyes.

But the silver lining is that the longer sales stay down, the more a pent up demand for new vehicles will build as more and more consumers will start to need a new vehicle while others will just want a new vehicle.

Automotive News recently published a fascinating chart showing how downturns in auto sales in 1979 and 1988 lasted three years before turning up again - in 1982 and 1991 respectively.

Applying that reasoning to the current downturn, it showed how current auto sales should show growth in 2010. Indeed sales could stabilize and even start to turn around before the end of this year.

But while this is extrapolating from past auto sales cycles, which offer a guide to timing rather than a guarantee of future trends, a growth in sales, once it sets in, is likely to be vigorous.

Indeed, Automotive News said the sales recovery in 1984 was particularly strong as "U.S. sales began to recover following three horrific years. Detroit's carmakers were manufacturing money ..."

"GM was earning so much money, it bought EDS for $2.55 billion (in 1984)... Ford poured billions into developing the Taurus, which arrived in 1985... and Chrysler piled up enough dough to buy AMC, including Jeep, in 1987."

Of course history is no guarantee of the future. But with top officials, including Fed Chairman Ben Bernanke, talking about positive signs in the economy, the so-called Great Recession may easing and with it the lockdown on auto sales.

- Peter C.T. Elsworth